Multi-axial woven fabric is used as reinforcement in producing constructional components. The strength requirements of a composite component varies throughout its structure and so the fabric used has to be tailored for each component. This commonly involves accurately cutting the fabric to size and layering it where required to provide a three dimensional structure. De-lamination between these layers can occur thereby weakening the component and so it is desirable for the independently formed layers to be physically tied to one another to provide inter layer strength.
A general aim of the present invention is to provide a process and loom weaving head for producing weaves including warp threads extending parallel to and/or inclined to the fabric take-off direction. Inclination of the warp threads may be in a horizontal and/or vertical plane. The warp yarns are woven with weft yarns which may extend in a direction generally perpendicular to the take-off direction and/or may be inclined in a horizontal and/or vertical plane.
In U.S. Pat. No. 4,140,156 a triaxial fabric is produced on a machine in which the two sets of bias yarns are created by displacement of heddles in the weftwise direction under the control of shifting means. Two sets of beating means that include opposing reeds are employed for beating up weft yarns to the fell of the fabric. The large number of heddles required need however to be movable weftwise, which leads to a machine of complex form.
A further aim of the invention is to provide a process and loom weaving head in which the formation of bias yarns in the weaving process can be advantageously carried out using novel yarn transfer means.
A further aim is to provide such a process and loom weaving head to enable complex weaves to be produced wherein the weave pattern can be selectively changed as the weaving process progresses. It is therefore possible to tailor the weave in order to provide desired shapes and/or strength characteristics.